Full Idea
The Peano Postulates can be proven in ZFC.
Clarification
ZFC is Zermelo-Fraenkel set theory, with the Axiom of Choice
Gist of Idea
Set theory can prove the Peano Postulates
Source
A.George / D.J.Velleman (Philosophies of Mathematics [2002], Ch.7)
Book Reference
George,A/Velleman D.J.: 'Philosophies of Mathematics' [Blackwell 2002], p.199